Two-stage container base
A blow-molded container including a finish and a base. The finish defines an opening at a first end of the container that provides access to an internal volume. The base includes a diaphragm and a standing surface. The diaphragm extends radially outward from a central push-up portion. The standing surface of the container is at a second end of the container. In response to an internal vacuum caused by hot-filling and closing the container, the diaphragm is configured to move passively from an as-blown first configuration to a second configuration in which the diaphragm is closer to the first end of the container as compared to the as-blown first configuration. The diaphragm is configured to move from the second configuration to an activated third configuration in which the diaphragm is closer to the first end of the container in response to the diaphragm being externally actuated by a tool.
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This application is a U.S. National Phase Application under 35 U.S.C. 371 of International Application No. PCT/US2015/046110, filed on Aug. 20, 2015 and published in English as WO 2016/029016 A1 on Feb. 25, 2016. This application claims the benefit of U.S. Provisional Patent Application No. 62/138,190 (filed on Mar. 25, 2015) and U.S. Provisional Patent Application No. 62/040,277 (filed on Aug. 21, 2014), the entire disclosures of all of which are incorporated herein by reference.
FIELDThe present disclosure relates to a two-stage container base.
BACKGROUNDThis section provides background information related to the present disclosure, which is not necessarily prior art.
As a result of environmental and other concerns, plastic containers, more specifically polyester and even more specifically polyethylene terephthalate (PET) containers, are now being used more than ever to package numerous commodities previously supplied in glass containers. Manufacturers and fillers, as well as consumers, have recognized that PET containers are lightweight, inexpensive, recyclable and manufacturable in large quantities.
Blow-molded plastic containers have become commonplace in packaging numerous commodities. PET is a crystallizable polymer, meaning that it is available in an amorphous form or a semi-crystalline form. The ability of a PET container to maintain its material integrity relates to the percentage of the PET container in crystalline form, also known as the “crystallinity” of the PET container. The following equation defines the percentage of crystallinity as a volume fraction:
where ρ is the density of the PET material; ρa is the density of pure amorphous PET material (1.333 g/cc); and ρc is the density of pure crystalline material (1.455 g/cc).
Container manufacturers use mechanical processing and thermal processing to increase the PET polymer crystallinity of a container. Mechanical processing involves orienting the amorphous material to achieve strain hardening. This processing commonly involves stretching an injection molded PET preform along a longitudinal axis and expanding the PET preform along a transverse or radial axis to form a PET container. The combination promotes what manufacturers define as biaxial orientation of the molecular structure in the container. Manufacturers of PET containers currently use mechanical processing to produce PET containers having approximately 20% crystallinity in the container's sidewall.
Thermal processing involves heating the material (either amorphous or semi-crystalline) to promote crystal growth. On amorphous material, thermal processing of PET material results in a spherulitic morphology that interferes with the transmission of light. In other words, the resulting crystalline material is opaque, and thus, generally undesirable. Used after mechanical processing, however, thermal processing results in higher crystallinity and excellent clarity for those portions of the container having biaxial molecular orientation. The thermal processing of an oriented PET container, which is known as heat setting, typically includes blow molding a PET preform against a mold heated to a temperature of approximately 250° F.-350° F. (approximately 121° C.-177° C.), and holding the blown container against the heated mold for approximately two (2) to five (5) seconds. Manufacturers of PET juice bottles, which must be hot-filled at approximately 185° F. (85° C.), currently use heat setting to produce PET bottles having an overall crystallinity in the range of approximately 25%-35%.
While current containers are suitable for their intended use, they are subject to improvement. For example, a reduced weight container that can immediately respond to internal vacuum created during filling in order to reduce the risk of the container being damaged on the fill line, and that can induce a positive pressure within the container to help fix and prevent denting of the container, would be desirable.
SUMMARYThis section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
The present teachings provide for a blow-molded container including a finish and a base portion. The finish defines an opening at a first end of the container that provides access to an internal volume defined by the container. The base portion includes a diaphragm and a standing surface. The diaphragm extends radially outward from a central push-up portion through which a longitudinal axis of the container extends. The standing surface of the container is at a second end of the container that is opposite to the first end. In response to an internal vacuum caused by hot-filling and closing the container, the diaphragm is configured to move passively from an as-blown first configuration to a second configuration in which the diaphragm is closer to the first end of the container as compared to the as-blown first configuration. The diaphragm is configured to move from the second configuration to an activated third configuration in which the diaphragm is closer to the first end of the container as compared to the second configuration in response to the diaphragm being actuated by an external tool.
The present teachings further provide for a blow-molded container including a finish and a base portion. The finish defines an opening at a first end of the container that provides access to an internal volume defined by the container. The base portion is at a second end of the container that is opposite to the first end. The base portion includes an external standing surface, an upstanding wall, a central push-up portion, a diaphragm, and a hinge. The external standing surface is at an outer diameter of the base portion. The upstanding wall extends from the external standing surface towards the first end of the container and is angled inward away from a sidewall of the container. The central push-up portion is at a center of the container. A longitudinal axis of the container extends through the central push-up portion. The diaphragm extends between the upstanding wall and the central push-up portion. The hinge is where the diaphragm mates with the upstanding wall. In the as-blown first configuration, the diaphragm is a first distance away from the external standing surface. Subsequent to the container being hot-filled, an internal vacuum within the container draws the diaphragm towards the first end of the container to a second configuration. In response to an external actuation force applied to the diaphragm when in the second configuration, the diaphragm moves from the second configuration to an activated third configuration. The diaphragm is closer to the first end of the container in the activated third configuration as compared to the first configuration.
The present teachings further provide for a method for filling a blow-molded container. The method includes hot-filling the container through an opening defining a finish at a first end of the container such that a base portion at a second end of the container passively moves from an as-blown first configuration to a second configuration in response to internal vacuum forces of the container. A diaphragm of the base portion is closer to the first end of the container in the second configuration than the as-blown first configuration. The diaphragm further includes applying external force to the base portion when the base portion is in the second configuration to move the base portion from the second configuration to an activated third configuration in which the base portion is closer to the first end of the container as compared to the second configuration.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTIONExample embodiments will now be described more fully with reference to the accompanying drawings.
Illustrated throughout the Figures are exemplary blow-molded containers 10, 110, 210, 310, 410, 510, and 610 according to the present teachings. The containers can be any suitable shape and size, such as 20 ounces for example. The containers can be made of any suitable material, such as any suitable blow-molded thermoplastic or bio-resin, including polyethylene terephthalate (PET), high density or low density polyethylene (HDPE, LDPE), polypropylene (PP), polyethylene naphthalate (PEN), a PET/PEN blend or copolymer, and the like, for example. The containers can be formed in any suitable manner, such as by stretch blow-molding.
The containers each include a lightweight container base portion 40, 140, 240, 340, 440, 540, and 640 for use with hot-fill product applications, such as juice, teas, enhanced water, and the like. As described herein, each of the base portions 40, 140, 240, 340, 440, 540, and 640 use at least two modes of operation to control vacuum and pressure within the filled container. A first mode provides for passive movement of the base under the forces of internal vacuum caused by the hot-fill process and subsequent cooling. A second mode is an active mode that includes application of external force to permanently form a base geometry into the container displacing internal volume to reduce or completely eliminate residual vacuum. Positive pressure in the container may also be achieved to help prevent and fix denting.
With initial reference to
With continued reference to
With particular reference to
After the container 10 is hot-filled and allowed to cool, an internal vacuum within the container 10 will passively draw the base portion 40 inward towards the first end 12 and to the second configuration B illustrated in
With reference to
As the base portion 40 is forced from the second configuration B to the third configuration C, the central push-up portion 42 and the diaphragm 50 are pushed further towards the first end 12. The diaphragm 50 pivots at the hinge portion 56. The curve radius of the diaphragm 50 may be reduced and the diaphragm 50 may temporarily distort or straighten, as illustrated in
As additional force is applied to the diaphragm 50, its position is reversed such that, as illustrated in
By forcing the base portion 40 to the activated third configuration C and into the internal volume 22 of the container 10, any remaining internal vacuum will be eliminated or nearly eliminated. Positive pressure may also be induced into the container 10 to help prevent and fix denting of the container 10. Such a positive pressure state in the container 10 allows for a lighter weight and thinner sidewall 30 that performs as good as, or better than, heavier containers with residual internal vacuum. The base portion 40 is formed using over-stroke, which leads to a base portion 40 with a lighter weight as compared to prior containers, uniform material distribution, and a reduced thickness of the sidewall 30. A clearance is provided between the standing surface 54 and the rest of the base portion 40 to prevent roll-out past the standing surface 54.
With reference to
The base portion 640 further includes an isolation rib 670. The isolation rib 670 is located at the isolation radius 658 and circumscribes the central push-up portion 42. The isolation rib 670 protrudes outward and allows the geometry of the base portion 640 to flex and absorb internal vacuum prior to the base portion 640 being mechanically inverted to the activated position C of
The base portion 640 includes an inversion height “h” (
The inversion height h can be any suitable height, and can depend on the diameter DD (see
The vacuum absorption of the base 640 (or any other suitable base) is the ease in which the diaphragm 650 is able to move to absorb initial vacuum as the diaphragm 650 moves from the first configuration A to the second configuration B, and thus prior to being subject to mechanical activation to move the diaphragm to the third configuration C. As the height h increases, the radius of the transitional radius hinge 656 typically decreases. The smaller the radius at 656, the more force (vacuum) that is required to move the base 640 from the first configuration A to the second configuration B, as compared to if the radius at 656 is larger. Therefore, as the height “h” increases, the base 640 will absorb less vacuum initially. As the “h” decreases the radius at 656 increases and the base 640 will move at lower vacuum forces absorbing more vacuum initially. In the second configuration B, when the base 640 is mechanically activated, the smaller height “h” will have a smaller vacuum absorbing capacity overall. For example, at a height h of 11.79 mm, the base 640 can absorb approximately 20.5 ml of volume. At a height h of 9.6 mm, the base 640 can absorb approximately 15.7 ml of volume. The larger the volume that the base 640 ultimately displaces, the lower the final residual vacuum in the container 610. But the initial force required to move the base 640 with the height h of 9.6 mm to relieve the vacuum prior to mechanical activation (mechanically moving the base 640 to configuration C) will be substantially less than the base 640 with the height h of 11.79 mm. Wall thickness of the container base 640 may change based on container size. As wall thickness decreases, the capacity to absorb vacuum increases.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
Claims
1. A blow-molded container comprising:
- a finish defining an opening at a first end of the container that provides access to an internal volume defined by the container; and
- a base portion including: a diaphragm extending radially outward from a central push-up portion through which a longitudinal axis of the container extends; a standing surface of the container at a second end of the container that is opposite to the first end;
- wherein: in response to an internal vacuum caused by hot-filling and closing the container, the diaphragm is configured to move passively from an as-blown first configuration to a second configuration in which the diaphragm is closer to the first end of the container as compared to the as-blown first configuration; and the diaphragm is configured to move from the second configuration to an activated third configuration in which the diaphragm is closer to the first end of the container as compared to the second configuration in response to the diaphragm being externally actuated by a tool; and
- an upstanding wall extending from the standing surface towards the first end of the container, the upstanding wall is angled away from a sidewall of the container and towards the central push-up portion;
- wherein at least a portion of the upstanding wall is configured to move towards the sidewall and subsequently away from the sidewall as the base portion moves from the second configuration to the third configuration.
2. The blow-molded container of claim 1, wherein the diaphragm is concave relative to the standing surface of the container in the as-blown first configuration, and the diaphragm is convex relative to the standing surface of the container in the activated third configuration.
3. The blow-molded container of claim 1, wherein the base portion further includes a hinge between the upstanding wall and the diaphragm, at least a portion of the hinge is configured to move towards the sidewall of the container and subsequently away from the sidewall of the container as the base portion moves from the second configuration to the third configuration.
4. The blow-molded container of claim 1, further comprising an isolation rib circumscribing the central push-up portion and protruding outward from the base portion away from the first end of the container.
5. The blow-molded container of claim 1, wherein the container has a ratio of diaphragm diameter to inversion height of the base portion defined between the standing surface and a peak of the diaphragm in the as-blown first configuration of greater than about 6:1.
6. The blow-molded container of claim 1, wherein the diaphragm continuously curves outward away from the longitudinal axis and the central push-up portion in the as-blown first configuration.
7. A blow-molded container comprising:
- a finish defining an opening at a first end of the container that provides access to an internal volume defined by the container; and
- a base portion at a second end of the container opposite to the first end, the base portion including: an external standing surface of the container at an outer diameter of the base portion; an upstanding wall extending from the external standing surface towards the first end of the container and angled inward away from a sidewall of the container; a central push-up portion at a center of the base portion, a longitudinal axis of the container extends through the central push-up portion; a diaphragm extending between the upstanding wall and the central push-up portion; and a hinge where the diaphragm mates with the upstanding wall;
- wherein: subsequent to the container being hot-filled an internal vacuum within the container draws the diaphragm from an as-blown first configuration towards the first end of the container to a second configuration; in response to an external actuation force applied to the diaphragm when in the second configuration, the diaphragm moves from the second configuration to an activated third configuration, the diaphragm is closer to the first end of the container in the activated third configuration as compared to the second configuration; and the base portion is configured such that the hinge moves towards the sidewall and then away from the sidewall as the base portion is moved from the second configuration to the activated third configuration by the external actuation force.
8. The blow-molded container of claim 7, wherein the diaphragm is concave relative to the external standing surface of the container in the as-blown first configuration, and the diaphragm is at least partially convex relative to the standing surface of the container in the activated third configuration.
9. The blow-molded container of claim 8, wherein the diaphragm is devoid of flat and convex portions in the as-blown first configuration.
10. The blow-molded container of claim 9, wherein the upstanding wall is integrated with the diaphragm.
11. The blow-molded container of claim 7, further comprising an isolation rib circumscribing the central push-up portion and protruding outward from the base portion away from the first end of the container.
12. The blow-molded container of claim 7, wherein the hinge is stationary as the central push-up portion and the diaphragm move towards the first end of the container.
13. The blow-molded container of claim 7, wherein the hinge and the upstanding wall are concave relative to the second end of the container in the as-blown first configuration.
14. The blow-molded container of claim 7, wherein the diaphragm changes shape as the diaphragm moves towards the first end of the container.
15. The blow-molded container of claim 7, wherein the base portion is configured such that the hinge remains stationary as the base portion is moved from the second configuration to the activated third configuration by the external actuation force.
16. The blow-molded container of claim 7, wherein the container has a ratio of diaphragm diameter to inversion height of the base portion defined between the standing surface and a peak of the diaphragm in the as-blown first configuration of greater than about 6:1.
17. The blow-molded container of claim 7, wherein the diaphragm continuously curves outward away from the longitudinal axis and the central push-up portion in the as-blown first configuration.
18. A method for filling a blow-molded container comprising:
- hot-filling the container through an opening defining a finish at a first end of the container such that a base portion at a second end of the container passively moves from an as-blown first configuration to a second configuration in response to internal vacuum forces of the container, a diaphragm of the base portion is closer to the first end of the container in the second configuration than the as-blown first configuration; and
- applying external force to the base portion when the base portion is in the second configuration to move the base portion from the second configuration to an activated third configuration in which the base portion is closer to the first end of the container as compared to the second configuration,
- wherein an upstanding wall of the base portion moves towards and away from a sidewall of the container as the diaphragm moves from the second configuration to the third configuration.
19. The method of claim 18, further comprising forming the blow-molded container to have an isolation rib circumscribing the central push-up portion and protruding outward from the base portion away from the first end of the container.
20. The method of claim 18, wherein the container has a ratio of diaphragm diameter to inversion height of the base portion defined between the standing surface and a peak of the diaphragm in the as-blown first configuration of greater than about 6:1.
21. The method of claim 18, wherein moving the base portion from the second configuration to the third configuration moves the base portion from a convex shape to a concave shape relative to an exterior of the base portion.
22. The method of claim 18, wherein the diaphragm retains a concave shape relative to an exterior of the base portion as the diaphragm moves from the second configuration to the third configuration.
23. The method of claim 18, further comprising forming the blow-molded container such that the diaphragm is: continuously concave relative to an exterior of the base portion, and is devoid of flat or convex portions.
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Type: Grant
Filed: Aug 20, 2015
Date of Patent: Aug 28, 2018
Patent Publication Number: 20170267391
Assignee: Amcor Limited (Hawthorn, Victoria)
Inventors: Luke A. Mast (Brooklyn, MI), Richard Steih (Jackson, MI), Kirk Edward Maki (Tecumseh, MI), Omkar Dole (Ann Arbor, MI), Mark Woloszyk (Chelsea, MI), David Downing (Manchester, MI)
Primary Examiner: Robert J Hicks
Application Number: 15/505,517
International Classification: B65D 1/02 (20060101); B65D 79/00 (20060101); B29C 49/12 (20060101); B29C 49/46 (20060101); B65D 23/00 (20060101); B29K 101/12 (20060101); B29K 105/00 (20060101); B29L 31/00 (20060101);